/Engine/Plugins/Online/OnlineServices/Source/OnlineServicesCommon/Public/Online/ExternalUICommon.h
IExternalUI.
virtual [TOnlineAsyncOpHandle](API\Plugins\OnlineServicesInterface\Online\TOnlineAsyncOpHandle)< [FExternalUIShowLoginUI](API\Plugins\OnlineServicesInterface\Online\FExternalUIShowLoginUI) > ShowLoginUI ( [FExternalUIShowLoginUI::Params](API\Plugins\OnlineServicesInterface\Online\FExternalUIShowLoginUI\Params) && Params )